Gear holding and centralizing device



Oct.

G. D. SCOTT GEAR HOLDING AND CENTRALIZING DEVIGE Filed Feb. 9, 1931 Gbercdd 1]. sum

Patented Oct. 18, 1932 UNITED STATES PATENT OFFICE GHEBALD D. SCOTT, OF WORCESTER, MASSACHUSETTS, ASSIGNOB TO THE HEALD MACHINE COMPANY, OF WORCESTER, MASSACHUSETTS, A COBPGRATION OF MASSA- CE'USETTS GEAR HOLDING AND CENTRA'LIZING DEVIGE Application filed February a, i931.

The present invention relates to an improved gear holding and centralizing device that is adapted to support a toothed gear with reference to its pitch line, or circle, so that grinding or cutting operations performed on an internal opening in the gear will be ahsolutely concentric, or coaxial, with the pitch circle of the teeth.

The device of the present invention is particularly adapted for the support of gears having teeth with wide faces, as well as gears with teeth of the spiral or herring-hone type, as will hereinafter more fully appear from the following description, with reference to the accompanying drawing, in which Fig. l is a view, partly in section, showing a gear held in a suitable chuck lay means of the centralizing device.

l 2 is a perspective view of one form of the centralizing device.

Fig. 3 is a view similar to Fig. 2 showing a modification oi the device.

Fig. l is a fragmentary view illustrating the cooperation of the device with the teeth of a gear.

Like reference characters refer to like parts in the diil'erent figures.

- Referring to Fig. '2, one embodiment of the invention is shown as comprising a base member 1 in the form of a ring, providing a plurality of recesses 2- in which are mounted flexible arms or supports 3 extending from the ring 1 at points suitably spaced around its periphery. Each of the arms 3 carries a pair of spaced enlarged worlr engaging portions 4, preferably spherical in form, although this shape may be varied somewhat if desired. As will hereinafter appeal, the diameter of the rin 1 for a given device is determined by the pitch diameter of the gear to be held, while the size of the work engaging portions 4 is determined by the circular pitch of the gear teeth.

In use, the device is slip ed over a gear 5, shown in dotted lines in 1 1, with the ring 1 substantially engaging t e side of the gear and the arms 3 extending over the faces of the ear teeth 6. With the ring 1 so positione the spherical portions 4 on the arms 3 lie between adjacent gear teeth 6 and en- Serial 30. 514,585.

gage opposedfaces of the teeth substantial incides with the number and spacing oi the radially movalole jaws '5' ct a chuck 8 or usual construction, shown in Fig. i, so that when a gear 5 held by the arms 3 is placed in the chuck 8 and the jaws T contracted, the portions 4 will simultaneously engage the gear teeth 6 and hold the gear firmly in position. And since the spherical portions l engage the gear teeth ti around the pitch circle, as snown in Fig. 4, the surfaces oi these portions 4 engage all the chuclr jaws 7 at the same distance from the center of the pitch circle. Consequently, any grinding or cutting operations performed on the interior oi the central opening 9 of the gear 5, as the chuck rotates, will be absolutely concentric, or coaxial, with the pitch circle of the teeth 6.

Referring to the embodiment shown in Fig. 3, a ring 10 supports flexible arms ll similar to the arms 3 of Fig. 2, and is cut away at 12 in a similar manner. Each arm 11 carries spaced ellipsoidal portions 18, that are particularly adapted for use with gears of soft steel or cast iron, since the ellipsoidal portions 13 by their line contact permit en gagement with greater areas of the gear teeth than in the previously described construction,

although the spherical portions 4 operate best on gears of hardened material. The centralizing device of Fig. 3 is applied to a gear in the same manner as described with reference to the device shown in Fig. 2.

When utilizing gear centralizing devices embodying the present invention, it is necessary to provide a variety of sizes correspond ing to the various pitch diameters of work ieces to be operated upon, the work contactmg portions 4 and 13, in each case, bein of such size as to contact with the gear teet at the pitch line. When it is desired to centralize a given gear, or workpiece, a device is selected of the proper diameter with work contacting ortions of the size required. for the teeth, a ter which the flexible arms 3 or 11 are adjusted to suit the angularity of the gear teeth, if any. In making such adjustments, the recesses 2 or 12 permit the flexible arms to be bent with a com aratively large radius at the points where t e are held by the rings, thus eliminating t e danger of m breakin the arms by repeated bendings. Obvious y, when centralizing straight toothed gears, the arms must be straight.

I claim,

1. A device for centering a gear comprising a base member, a plurality of flexible arms extending from said base, and spaced enlarged portions on said arms substantially circular in cross section and adapted to en- E gage with teeth on a gearv substantially at the pitch line.

2. A device for centering a gear in a clamping device comprising a base member, a plurality of flexible arms extending from the said base, and a plurality of members car ried by said arms engageable between teeth on said gear and the clamping device, said members being so spaced as to engage the gear teeth at different points around the pitch circle.

ranged to engage sa-id gear adjacent opposite edges thereof. GHERALD D. SCOTT.

3. A. device for clamping a gear in a clamping device comprising a base member adapted to engage one surface of a gear, flexible arms carried by said base adapted to extend along 5 the teeth of said gear, and spaced, substantially spherical portions mounted on each of said arms adapted to engage between said teeth and the cramping member, the diameter of the spaced portions being such as to engage the gear teeth substantially at the pitch line.

4. A device for centering a gear in a clamping device com rising a ring, a plurality of recesses in sai rin a plurality of flexible arms mounted in 581d recesses, and a plurality of spaced work engaging portions carried b said arms.

5. device for centering a gear in a clamping device comprising a. base, a plurality of flexible arms, and a plurality of enlarged portions on said arms adapted to engage the teeth of a gear by a plurality of point contacts around the itch line.

6. A device of t e class described, comprising an annulus, a plurality of flexible supporting arms extending from said annulus recesses in said annulus within which said flexible arms .are mounted, said recesses being larger than said arms, whereby said arms are capable of angular adjustment, and enlarged work engaging portions on said arms.

7. A device for centering a gear in a clamping device comprising a base member, a plura 1 ty of flexible arms extending from said 65 base, and a pluralityof spaced members car- 

